Giant scorpion
From Ardrana
Giant scorpions are vicious predators that live almost anywhere, including relatively cold places such as dungeons, though they favor deserts and warm lands. These creatures are giant versions of the normal 4-inch-long scorpion found in desert climes.
The giant scorpion has a green carapace and yellowish green legs and pincers. The segmented tail is black, with a vicious stinger on the end. There is a bitter smell associated with the scorpion, which probably comes from the venom. They make an unnerving scrabbling sound as they travel across dungeon floors.
Note: Giant scorpions originally appeared in this form in the 2nd Edition Monstrous Manual for the AD&D game from TSR. Their use here is for the purposes of providing context for the campaign only.